U.S. Pat. No. 3,161,676 describes a process for the preparation of a substituted alkyl urea by reacting a carbamic acid ester with a primary and sterically unhindered secondary aliphatic amines in the presence of a metal compound Lewis acid catalyst, such as cupric acetate.
There is no known prior art which describes the preparation of N-monosubstituted carbamic acid esters by reacting an unsubstituted carbamic acid ester and an aromatic primary amine in the presence of a monohydric aliphatic alcohol with or without the use of a tertiary amine catalyst.
Many important commercial applications have been developed for the carbamic acid ester products of this invention, for example, as agricultural chemicals and chemical intermediates which may be converted to the corresponding isocyanate and alcohol by thermal decomposition or other methods described in the prior art.